src/share/vm/opto/macro.cpp

rev 9640 : 8144993: Elide redundant memory barrier after AllocationNode
Summary: Elide memory barrier for AllocationNode when it doesn't escape in initializer and has an MemBarRelease node at exit of initializer method.
Reviewed-by: duke

*** 1525,1534 ****
--- 1525,1535 ----
      // escape no need for a MemBarStoreStore. Otherwise we need a
      // MemBarStoreStore so that stores that initialize this object
      // can't be reordered with a subsequent store that makes this
      // object accessible by other threads.
      if (!alloc->does_not_escape_thread() &&
+         !alloc->is_allocation_MemBar_redundant() &&
          (init == NULL || !init->is_complete_with_arraycopy())) {
        if (init == NULL || init->req() < InitializeNode::RawStores) {
          // No InitializeNode or no stores captured by zeroing
          // elimination. Simply add the MemBarStoreStore after object
          // initialization.